Color photographs which have been widely popularized in these days have much improved to be easily and rapidly available anywhere due to the improvement in photographic materials themselves and developing and processing techniques. For color printing papers to be used to produce viewing color prints, in particular, the realization of photographic materials containing high silver chloride emulsions has brought about highly-rapid processing of the materials. The market where highly-rapid processing of photographic materials is being promoted needs the improvement in the sharpness and the color reproducibility of photographic materials to give high-quality photographic images and, in addition, further needs the provision of such high-quality photographic products at low costs.
The color image forming method which is most generally employed in processing silver halide color photographic materials is such that the exposed silver halides in the material are reacted with, as the oxidizing agent, an oxidized, aromatic primary amine color developing agent to form indophenol, indoaniline, indamine, azomethine, phenoxazine, phenazine and the like dyes. According to the method, employed is subtractive color photography to reproduce color images. In general, color images are formed by varying the amounts of three dyes comprised of yellow, magenta and cyan dyes to be formed in the processed photographic material.
To form cyan color images, generally used are phenol or naphthol cyan couplers. However, since these couplers have unfavorable absorption in the green light range and the blue light range, these have a serious problem in that they noticeably worsen the blue and green color reproducibility. Therefore, it is strongly desired to solve the problem.
As one means for solving the problem, it has been proposed to employ 2,4-diphenylimidazole cyan couplers. The dyes to be formed from these couplers have more reduced unfavorable absorption in the green and blue ranges than those to be formed from conventional couplers, and the color reproducibility of these couplers has surely been improved in some degree. However, it is difficult to say that the color reproducibility of these couplers is satisfactory and further improvement in their color reproducibility is desired. In particular, these couplers have serious problems in that their reactivity with oxidation products of developing agents or, that is, their coupling activity is low and that the heat resistance and the light fastness of the dyes to be formed from these couplers are extremely low. For these reasons, these couplers cannot be put to practical use.
Pyrazoloazole cyan couplers are better than conventional cyan couplers in that the unfavorable absorption of the dyes to be formed from the pyrazoloazole cyan couplers in the green and blue ranges is less than that of the dyes to be formed from the conventional cyan couplers, but the pyrazoloazole cyan couplers still have problems in that their color reproducibility is not satisfactory and that their coloring property is extremely bad.
As couplers of forming dyes with excellent color hue, pyrrolopyrazole cyan couplers are known. These couplers are better than the above-mentioned pyrazoloazole cyan couplers with respect to their color reproducibility but are not still satisfactory. They have a drawback in that they give much color fog in the non-exposed area. In addition, their coloring property is not still in a satisfactory level.
As cyan couplers which are free from the above-mentioned problems or, that is, those having a good coloring property and giving dyes with reduced unfavorable absorption in the green and blue ranges, European Patents 0,491,197 and 0,488,248 have proposed pyrroloazole cyan couplers having particular substituents. These cyan couplers form dyes having an excellent absorbing characteristic or, that is, dyes having a large molar extinction coefficient and having a sharp spectral profile in the short wavelength range (characterized in that the unfavorable absorption in the green range and the blue range has been reduced), and their coloring property or, that is, their reactivity with oxidation products of developing agents is high while the heat resistance and the light fastness of the dyes to be formed from them are excellently high. From these viewpoints, the cyan couplers are favorable.
On the other hand, the support in color printing papers is designed in such a way that the base of the support is coated with a polyolefin layer containing titanium dioxide that has been kneaded and dispersed thereinto, on its surface side where photographic emulsions are to be coated thereover, in order to improve its water-proofness and its light reflectivity. Various means have heretofore been known to improve the sharpness of silver halide photographic materials having such a reflective support. Such means include, for example, (1) anti-irradiation by the use of water-soluble dyes, (2) anti-halation by the use of colloidal silvers, mordant dyes, fine grains of solid dyes, etc., (3) protection of the support from light by increasing the amount of the white pigment to be in the laminate resin on a paper support or by additionally coating a gelatin dispersion of a white pigment on the support, etc.
Of these means, however, (1) and (2) have serious problems in that they result in noticeable decrease in the sensitivity of photographic materials and result in increase in the color stains in the processed photographic materials. According to the means (3), the sharpness of photographic materials may be improved noticeably by coating a gelatin dispersion containing a white pigment on the support, but the coating of the white pigment-containing gelatin dispersion worsens the storability of non-exposed photographic materials and increases the total thickness of photographic materials, thereby causing various new problems in that the stability of photographic materials during their processing is lowered, the drying speed thereof is lowered so that the materials are not applicable to rapid processing, the production costs of the materials are elevated, etc.
On the other hand, it is known that the sharpness of photographic materials may be remarkably improved by increasing the content of the white pigment in the polyolefin laminate on the support. However, such increase results in the elevation of the production costs of photographic materials so that it is impracticable. JP-A 49-30446, 2-58042, 1-142549, 4-256947, 4-256948, etc. have disclosed reflective supports having two or more polyolefin layers having different white pigment contents. (The term "JP-A" as used herein means an "unexamined published Japanese patent application".) According to these constitutions, it has been known that the amount of the white pigment to be used may be reduced while the sharpness of photographic materials is kept high and therefore the proposed constitutions are advantageous in view of the production costs.
However, it has been found that when pressure is applied to a photographic material having a support comprising such a multi-layered resin layer before its development, the area of the material to which pressure was applied is fogged during its processing or, that is, the processed material is to have stress marks around the area. This problem is not so significant when the photographic material contains conventional phenol or naphthol cyan couplers, but is serious when the material contains cyan couplers of a general formula (Ia) which will be mentioned hereinafter so as to have an improved coloring property and improved color reproducibility. In addition, it has been found that the above-mentioned stress marks appear noticeably in stored photographic materials though appearing in some degree in fresh photographic materials. Moreover, it has been found that this problem is more serious in silver halide emulsion grains having an extremely high silver chloride content.